release-notes-1.0-b1.html

struts api,学习使用struts必备的文档

  <ul>
  <li>Initial implementation of a JDBC data source that implements the
      <code>javax.sql.DataSource</code> interface from the JDBC 2.0 Standard
      Extensions API.  This implementation may be configured based on new
      extensions to the Struts configuration file DTD, and the configured
      data sources / connection pools are made available to application
      components as a servlet context attribute (i.e. an application scope
      bean).</li>
  <li>The previous implementation of <code>MessageResources</code>, which was
      ultimately based on <code>java.util.ResourceBundle</code>, has been
      completely replaced and re-implemented.  The primary features of the
      new implementation are:
      <ul>
      <li>All components stored as servlet context attributes now implement
          the <code>java.io.Serializable</code> interface, to better integrate
          with application servers that prefer this.</li>
      <li>The <code>MessageResources</code> and <code>MessageResourcesFactory</code>
          classes have been abstracted so that you can easily create your
          own implementations that derive their message strings from resources
          other than property files.</li>
      </ul>
</li>
  <li>Property gets and sets made through <code>PropertyUtils</code> can now
      use a new syntax for indexed and nested properties.</li>
  <li>Conversion to and from numeric types now support a configurable default
      value to use when conversion fails.</li>
  </ul>

  <p>The following major new features have been added to the
  <em>Struts Example Application</em>:</p>
  <ul>
  <li>The form beans used in the example application now use request scope
      rather than session scope.  This is the preferred approach for single
      page forms that contain <em>all</em> of your relevant properties,
      because there is no need to maintain such form beans across requests.
      Note that the action classes have been coded so that they work with
      either request scope or session scope beans.</li>
  <li>The Struts Example Application has been updated to utilize the new
      (separated) custom tag libraries, rather than the old combined one,
      as well as the latest features of the tags being used.</li>
  <li>A "Walking Tour of the Struts Example Application" has been added, to
      highlight features for newcomers to Struts.</li>
  </ul>

  <p>The following major new documentation updates have been added to
  Struts:</p>
  <ul>
  <li>All documentation is generated from XML input files, using a standard
      stylesheet to create a common look and feel.</li>
  <li>Developer Guides for the Java classes in the
      <code>org.apache.struts.digester</code> and
      <code>org.apache.struts.util</code> packages.</li>
  <li>Developer Guides for the following Struts custom tag libraries have
      been added:  <code>struts-bean</code>, <code>struts-html</code>,
      <code>struts-logic</code>, and <code>struts-template</code>.</li>
  <li>The Struts Users Guide has been brought up to date with respect to
      all of the changes since Struts 0.5, and separated into multiple
      HTML pages for easy reading.</li>
  <li>Installation information has been updated to include platform-specific
      notes, issues, and workarounds.</li>
  <li>A new resources page now points at external information and resources
      related to Struts.</li>
  <li>A new example application, <code>struts-blank</code>, is included as a
      quick starting point for new application development.</li>
  </ul>

  </div>


  <h2 id="Changes">Changes and Bug Fixes</h2>
<div class="indent">

  <p>The following changes and bug fixes to the controller servlet and
  associated classes (package <code>org.apache.struts.action</code>) have
  occurred:</p>
  <ul>
  <li>The <code>ActionMapping</code> interface has been converted to a base
      class instead, to reduce the impact of future enhancements.  Anyone who
      has extended the <code>ActionMappingBase</code> convenience base class
      (which has been deprecated) should extend <code>ActionMapping</code>
      instead.</li>
  <li>In conjunction with the new configuration file format mentioned above,
      the properties of <code>ActionMapping</code> have been substantially
      updated.  See the
      <a href="../../api/org/apache/struts/action/ActionMapping.html">API
      Documentation</a> for more information</li>
  <li>The <code>Action</code> interface has been converted to a base class
      instead, to reduce the impact of future enhancements.  Anyone who has
      extended the <code>ActionBase</code> convenience base class (which
      has been deprecated) should extend <code>Action</code> instead.</li>
  <li>In conjunction with the above change, the <code>servlet</code>
      argument has been removed from the parameter list for the
      <code>perform()</code> method, because it is now redundant -- the
      associated servlet is set via the <code>setServlet()</code> method
      when the <code>Action</code> instance is first created.</li>
  <li>Responsibility for creating <code>Action</code> instances has been moved
      from <code>ActionMapping</code> to the controller servlet, so that
      instance lifecycle management can be performed.  As a side effect of this
      change, if you had two actions that used the same Action class name,
      there will now be only one (shared) instance of the Action class,
      rather than two.</li>
  <li>New <code>log(String, int)</code> method that logs the associated message
      only if you have configured the debugging detail level for the servlet to
      an equal or higher value.</li>
  <li>In <code>ActionServlet</code>, the functionality to populate form bean
      parameters from a request, and the functionality to validate the form
      bean's contents, has been separated into two methods that can be
      overridden individually if required.</li>
  <li>The <code>ActionServlet</code> functionality to call the
      <code>validate()</code> method of a form bean is skipped if the user
      pressed the Cancel key (i.e. the submit button created by the
      <code>&lt;html:cancel&gt;</code> custom tag), or if the selected
      mapping does not define an input form to return control to.</li>
  <li>The controller servlet may now be used as the target of a
      <code>RequestDispatcher.include()</code> or
      <code>&lt;jsp:include/&gt;</code> call.  Previously, it would mistakenly
      use the original request URI, rather than the included path, to calculate
      which action class to execute.</li>
  <li>The <code>ActionMappings.getUnknown()</code> method now takes the current
      request as an parameter, so that context-sensitive decisions can be
      made.</li>
  <li>When the controller servlet processes an <code>ActionForward</code> that
      has the <code>redirect</code> property set, it now performs URL rewriting
      to maintain session state even if cookies are not being used.</li>
  <li>The <code>ActionErrors</code> class now includes a method that will
      return an Iterator over the error messages related to a particular
      input field.</li>
  </ul>

  <p>The following changes and bug fixes to the Digester module
  (package <code>org.apache.struts.digester</code>) have occurred:</p>
  <ul>
  <li>The <code>Digester.resolveEntity()</code> method has been enhanced
      to correctly handle local URIs so that it works with resources loaded via
      <code>Class.getResource()</code>.</li>
  <li>The input source handed to the Digester is now closed, even if a
      parsing exception is throw.</li>
  </ul>

  <p>The following changes and bug fixes to the <em>struts-bean</em> custom
  tag library (package <code>org.apache.struts.taglib.bean</code>) have
  occurred:</p>
  <ul>
  <li>By default, the <code>&lt;bean:write&gt;</code> tag will filter output
      for characters sensitive to HTML.  You can turn this off by adding a
      <code>filter="false"</code> attribute.</li>
  <li>When performing a <code>&lt;bean:include&gt;</code> in a page that is
      part of a session, pass the session identifier along on the generated
      request so that it will be part of the same session.</li>
  <li>The <code>&lt;bean:define&gt;</code> tag can now create
      beans directly from the <code>value</code> attribute, if desired.</li>
  <li>The <code>&lt;bean:define&gt;</code> tag now accepts an optional
      <code>toScope</code> attribute, to declare which scope the new bean
      should be created in.  The default remains <code>page</code> scope.</li>
  <li>Default values can now be specified on <code>&lt;bean:cookie&gt;</code>,
      <code>&lt;bean:header&gt;</code>, and
      <code>&lt;bean:parameter&gt;</code> tags, which are used when the
      corresponding value is not present in the current request.</li>
  </ul>

  <p>The following changes and bug fixes to the <em>struts-html</em> custom
  tag library (package <code>org.apache.struts.taglib.html</code>) have
  occurred:</p>
  <ul>
  <li>
<strong>WARNING</strong> - When the Struts 0.5 tag library was originally
      split into separate libraries, this library was named
      <em>struts-form</em>, to reflect the fact that the majority of tags
      related to creating input forms.  It has been renamed to
      <em>struts-html</em> to reflect the fact that all of the tags in this
      library are relevant only when building HTML-based user interfaces.</li>
  <li>The <code>&lt;html:html&gt;</code> tag now supports a
      <code>locale="true"</code> attribute that requests the same Locale
      negotiation (based on the presence of an <code>Accept-Language</code>
      header) that is performed by the controller servlet.</li>
  <li>The <code>&lt;html:link&gt;</code> tag now supports the ability to add
      a single request parameter (based on a bean property) in addition to the
      ability to add request parameters from a Map.</li>
  <li>The <code>&lt;html:errors&gt;</code> tag lets you select only the error
      messages related to a particular input field, or all errors.</li>
  <li>The <code>&lt;html:password&gt;</code> tag now optionally redisplays
      the previous value of the input field.</li>
  <li>The value returned by a <code>&lt;html:multibox&gt;</code> tag can now
      be specified in the body of the tag, as well as via the
      <code>value</code> attribute.</li>
  </ul>

  <p>The following changes and bug fixes to the <em>struts-logic</em>
  custom tag library (package <code>org.apache.struts.taglib.logic</code>)
  have occurred:</p>
  <ul>
  <li>The <code>&lt;logic:present&gt;</code> and
      <code>&lt;logic:notPresent&gt;</code> tags now accept a <code>role</code>
      attribute that allows you to detect whether the currently authenticated
      user does, or does not, possess a particular security role.</li>
  </ul>

  <p>The following changes and bug fixes to the <em>struts-template</em>
  custom tag library (package <code>org.apache.struts.taglib.template</code>)
  have occurred:</p>
  <ul>
  <li>The <code>&lt;template:put&gt;</code> tag now accepts a
      <code>direct</code> attribute that causes the content being put to be
      rendered directly, rather than being included.</li>
  </ul>

  <p>The following changes and bug fixes to the Utilities package
  (package <code>org.apache.struts.util</code>) have occurred:</p>
  <ul>
  <li>Fixed <code>PropertyUtils.getPropertyType()</code> to correctly return
      the underlying element type even if there was a non-indexed property
      getter method.</li>
  <li>Added a missing "return" statement to
      <code>PropertyUtils.setIndexedProperty()</code>.</li>
  <li>Functionality in <code>BeanUtils</code> that previously duplicated
      functionality that was earlier moved to <code>PropertyUtils</code>
      has been removed.</li>
  <li>Fixed <code>PropertyUtils.copyProperties()</code> to skip cases where
      the origin bean has a getter method but the destination bean does not
      have a setter method.</li>
  <li>Added <code>BeanUtils.cloneBean()</code> to create a new instance of
      an existing bean, and copy all known properties, even if the bean class
      does not implement <code>Cloneable</code>.</li>
  <li>The <code>BeanUtils</code> class has been refactored so that it, and
      the associated <code>ConvertUtils</code> and <code>PropertyUtils</code>
      classes, can easily be used without having to have the servlet API
      classes available on the classpath.</li>
  <li>Property introspection is now smarter, so that you can access public
      methods declared in an implemented interface, even if the class itself
      is not public.</li>
  </ul>

  <p>The following changes and bug fixes to the Struts Example Application
  (package <code>org.apache.struts.example</code> and the corresponding web
  components) have occurred:</p>
  <ul>
  <li>Used the <code>reset()</code> methods defined by the
      <code>ActionForm</code> interface to reset form bean properties to
      default values.  This is particularly important to make boolean
      properties (represented visually by checkboxes) work correctly.</li>
  <li>Eliminate the special-case handling of null String values in the
      form beans.  Such handling is not necessary because the custom tags
      correctly deal with null String values.</li>
  <li>Use the <code>PropertyUtils.copyProperties()</code> method to initially
      populate form beans from underlying data objects, and to update date
      objects when a transaction is successfully completed.  Note that using
      this approach dramatically lessens an action class's dependence on the
      specific properties of the form bean and corresponding data object
      in many use cases.</li>
  <li>Added an <code>autoConnect</code> boolean property to the Subscription
      data object, primarily to illustrate that representing a boolean
      property with a checkbox now works correctly if you set the property
      to <code>false</code> in the <code>reset()</code> method of your
      form beans.</li>
  </ul>

  </div>

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